Tracking an invader: range expansion of Culicoides insignis in the Southeastern United States

Culicoides insignis has been historically known as a neotropical biting midge species with a range extending from Argentina, northward through the Caribbean and peninsular Florida, to extreme southern Georgia. However, during an ongoing, ten-state, multi-year survey of Culicoides species in the Southeastern United States, C. insignis has been found at an increasing frequency outside its historic range. In addition, C. insignis was recently collected from a site in north central Louisiana, which continues a pattern of northwestern range expansion. This species of Ceratopogonid is of particular interest due to its ability to serve as a vector of bluetongue virus (BTV), as it does in South America and the Caribbean. In the Southeastern United States, there are currently several enzootic BTV serotypes that are transmitted by other native Culicoides species, including C. sonorensis. However, the possibility exists for C. insignis to spread both enzootic BTV serotypes as well as introduced, exotic BTV serotypes to wild and domestic ruminants in that region.